Modern wind turbines are used to supply electricity into the electrical grid. Wind turbines generally comprise a tower and a rotor arranged on the tower. The rotor, which typically comprises a hub and a plurality of blades, is set into rotation under the influence of the wind on the blades. Said rotation generates a torque that is normally transmitted through a rotor shaft to a generator, either directly or through the use of a gearbox. This way, the generator produces electricity which can be supplied to the electrical grid.
Gearboxes, bearings and other components of the wind turbine drive train are mechanical devices that experience wear. Even with the drive train mounted in a housing or nacelle and thus protected from direct exposure to the elements, components such as gearboxes and bearings can indirectly experience stress from extreme environmental conditions because of their coupling to large rotors. Thus, gearboxes and other components of the drive train in wind turbines require occasional repair and/or replacement. These drive trains use many mechanically connected components that may require separation to perform the repair and/or replacement.
In at least one known method for replacing a gearbox in a wind turbine, a crane is required to lift the gearbox out of an open nacelle. In a typical wind turbine, a large rotor is fastened to the other end of the main shaft. This rotor has several blades attached to a hub, so to prevent the main shaft from bending or the rotor from becoming tilted. The blade/hub assembly has to be removed from the turbine before the gearbox can be removed. The size of the wind turbines makes servicing difficult and expensive, as at the 65 meters or greater height of some wind turbines used in generator farms, a large crane is required. Two cranes are required in some cases, because the entire rotor set must be removed in some cases and brought to the ground. A second crane is used to grab the bottom blade of the rotor and to “tail it out,” i.e., make it flat in the air so that it can be set on the ground. Thus, any repair methods that can be performed up-tower can avoid much of the effort described above.
At least one known method of removing mechanically-connected parts in the wind turbine drive train is to use large amounts of axial force in order to pry the components apart. Using these large axial forces to separate parts carries a large risk of damaging the parts which would in turn mean that replacement parts would need to be provided. Also, lowering the entire assembly to the ground via crane is both overly time-consuming and expensive.
Thus, a need exists for a maintenance tool that can be easily transported to the wind turbine site, can be hoisted up-tower, and can assist in separating mechanically-connected components without damaging the components.